This presentation talks about how to use GlusterFS containers in Docker. If you need more details please refer http://www.humblec.com/building-glusterfs-in-a-docker-container/ Demo Video # https://youtu.be/4Xf8pmDEZYw

1. GlusterFS Container

2. Gluster Meetup June 2016,
Bangalore, India
Mohamed Ashiq Liyazudeen
Associate Software Engineer @redhat
@ IRC:ashiq on freenode,
github: github.com/MohamedAshiqrh,
mailto: ashiq333@gmail.com
Humble Devassy Chirammal
Senior Software Engineer @redhat
@ IRC : hchiramm on freenode,
github : github.com/humblec,
mailto : humble.devassy@gmail.com
website : humblec.com

3. Gluster Meetup June 2016,
Bangalore, India
Agenda
● GlusterFS
● Docker
● Why containers?
● GlusterFS Container
● Q&A

4. Gluster Meetup June 2016,
Bangalore, India
GlusterFS
● Open-source scale-out distributed file system.
● Aggregates various storage servers over
network interconnects into one large parallel
network file system.
● User space filesystem with no dedicated
metadata server that helps us achieve scalability.

5. Gluster Meetup June 2016,
Bangalore, India
Docker
● Docker offers a simple way to package an application
and its runtime dependencies into a single container.
● Docker Container uses shared kernel concept and are
much more efficient than hypervisors in system
resource terms.
● Docker is both a development tool and a runtime
environment.

6. Gluster Meetup June 2016,
Bangalore, India
Container Architecture
Source: Docker Inc.

7. Gluster Meetup June 2016,
Bangalore, India
Docker Concepts
● Docker Image is a static specification of what the
container should be in runtime, including the application
code inside the container and runtime configuration
settings. They are Read-only.

8. Gluster Meetup June 2016,
Bangalore, India
Docker Concepts
● Docker container always starts with an image and is
considered an instantiation of that image.

9. Gluster Meetup June 2016,
Bangalore, India
Why Container?
● Shared Kernel
● Environment Regardless
● Isolation
● Minimizes System Drift
● Shipping
● Cleaner updates and Manageable state change
● Storage Hyper-converged Environment Support

10. Gluster Meetup June 2016,
Bangalore, India
GlusterFS Container
● Systemd is used in GlusterFS container because
gluster needs to run more than one process in the
container.
● GlusterFS configuration is made persistent as
containers writable layer is not persistent in case of re-
spawn.
● Even though GlusterFS can operate on any networking
model, we prefer host networking (--net=host) of Docker
for better performance on storage network.

11. Gluster Meetup June 2016,
Bangalore, India
Steps Breakdown
● Pull the image
● Prepare the node for GlusterFS configuration
persistence(create directories /var/lib/glusterd,
/var/log/glusterfs and /etc/glusterfs).
● /var/lib/glusterd – volume management files
● /var/log/glusterfs – gluster log files
● /etc/glusterfs – glusterd management files
● GlusterFS prerequisites(like opening the required port).
● Start GlusterFS container.

12. Gluster Meetup June 2016,
Bangalore, India
GlusterFS Container
● # docker pull gluster/gluster-centos:gluster3u7_centos7
● # mkdir -p /etc/glusterfs /var/lib/glusterd
/var/log/glusterfs
● # modprobe dm_snapshot (in case of snapshot)
● # docker run --name gluster -d -v
/etc/glusterfs:/etc/glusterfs:z -v
/var/lib/glusterd:/var/lib/glusterd:z -v
/var/log/glusterfs:/var/log/glusterfs:z -v
/sys/fs/cgroup:/sys/fs/cgroup:ro --net=host
--privileged=true -v /dev:/dev gluster/gluster-
centos:gluster3u7_centos7

13. Gluster Meetup June 2016,
Bangalore, India
GlusterFS docker run
As seen before its a long command, lets check why all
the options are required.
● As Gluster needs to run more than one service in a
container, It needs systemd. For systemd to run in a
container “--privileged=true”.
● Host Networking (--net=host) of Docker for better
performance on storage network.

14. Gluster Meetup June 2016,
Bangalore, India
Network options
● Docker Network “none”, adds a container to a
container-specific network stack.
● Docker Network ”bridge”, represents the bridge network
(default docker0).
● Docker Network ”host”, adds a container on the hosts
network stack.

15. Gluster Meetup June 2016,
Bangalore, India
Persistence of Gluster configuration
● -v /etc/glusterfs:/etc/glusterfs:z -v
/var/lib/glusterd:/var/lib/glusterd:z -v
/var/log/glusterfs:/var/log/glusterfs:z
● The above ensures that the gluster configuration are
persistent, In the command.
● As we mention “:z” - SELinux labels are automatically
reset to svirt_sandbox_file_t so that the container can
interact with the Host directory.

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Bangalore, India
Gluster Peer Probe

17. Gluster Meetup June 2016,
Bangalore, India
Trusted Storage Pool

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Bangalore, India
References
● http://humblec.com/building-glusterfs-in-a-docker-container/
● http://humblec.com/gluster_containers_in_kubernetes_clust
● http://humblec.com/glusterfs-containers-docker-kubernetes-
● https://hub.docker.com/r/gluster/
● https://github.com/gluster/docker
● https://github.com/gluster/glusterfs-kubernetes-openshift

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Bangalore, India
Thanks !
Q & A